This invention relates to cutting hand tools for cutting pipes of aluminum, plastics or the like, electric cables, thick wires, etc.
Tools of this type include the cutting pliers disclosed in U.S. Pat. No. 3,210,844 and comprising a stationary handle having a first cutting jaw and a pivoted element turnably mounted on the stationary handle. The pivoted element has a second cutting jaw and a toothed segment. The stationary handle carries a ratchet wheel meshing with the toothed segment and is provided with a movable handle pivoted to the handle. When the movable handle is operated, a wedge-shaped ratchet dog mounted thereon and adapted to intermittently engage the ratchet wheel turns the ratchet wheel, which causes the toothed segment to turn the second cutting jaw for cutting operation.
The pliers have difficulty in cutting a workpiece of small diameter with the base portions of the jaws since the workpiece slips outward to a stable position before being firmly clamped by the jaws. Thus, when cutting circular workpieces, the two jaws must apply a cutting force to the workpiece while holding approximately diametrically opposed portions thereof; otherwise the workpiece would slip off the jaws, or would not be cut before slipping to a stable position on the jaws. When initiating a cutting operation, the jaws, which are held in their fully opened position by the action of a spring on the pivoted element, need to be brought into clamping engagement with the workpiece by moving the movable handle a number of times. The idle strokes of the handle required before the substantial cutting operation lead to labor and time losses.
These drawbacks of the prior art are still unavoidable even when the jaws are modified to such a shape as to prevent the escape of the workpiece, for example, to the circular are shape (of receiving surface) shown in FIG. 1. In fact, the foregoing drawbacks will invariably result when a single tool is adapted for use with various workpieces of varying diameters.